Together with the imaging dose, we need to consider and weight the gains from intrafraction monitoring and gated treatment. These gains include improving the accuracy of delivered dose, so that the planned treatment dose is delivered efficiently to the tumour, and the geometric accuracy that would allow reduction in the safety margin introduced to compensate for treatment. We have demonstrated significant improvements in tumour dose from 60% to 95% of the intended dose distribution by gating with 3mm/5s tolerance as shown in Figure 1.